Radiation dose-response curves for normal tissues define the probability of injury as a function of effective dose to the tissue. There are very few dose-response curves in the conventional radiation oncology literature and none that have taken account of censoring that results from the death of patients prior to and during the period that late radiation injuries are expressed. The objective of this study is to obtain the dose-response curves for various normal tissues by analyzing outcomes in approximately 440 patients from a single institution who were inadvertently irradiated to doses 10 to 45% in excess of the prescribed doses. In addition, case-control studies will be performed to identify factors other than those that may affect radiation sensitivity. Specifically we propose: 1. To obtain information on the early (severe) and late radiation injuries that resulted from overdoses of 10 to 45%. This information will be obtained from radiotherapy charts, hospital charts, referring physicians, and legal depositions. These overdoses occurred over a 16 month period in a well defined group of 440 patients, and the amount of overdose is approximately evenly distributed among these patients. 2. To perform dose-response analysis using-techniques developed specifically for analyzing late injuries in censored populations. This analysis will be performed for individual organs and tissues for which complications were recorded, and will include fractionation and volume factors. 3. To obtain, from the same sources as in (1), information on factors other than radiation dose that may have influenced the radiation response. These factors include other treatments, previous or concurrent diseases (diabetes mellitus, autoimmune collagen disease, etc.), and physical findings (blood pressure, congenital defects etc.). 4. To perform case-control studies using dose-matched controls to ascertain the significance (relative risk) of factors other than dose in the radiation response.